Approach sequencing at LGW
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Approach sequencing at LGW
Approach sequencing at LGW
This one is for the LGW approach/director controllers and the 'drivers'. I tried floating this through my company a while ago but with no response, so its time to see what pprune can make of it!
When LGW starts to get busy and aircraft are holding, it is not uncommon to be taken off the hold and given extended vectoring, with speed control, round to the final approach. This can vary between 30 and 80 miles and the biggest variation I have seen in fuel used from the hold in a 737 is between 300 and 800 kgs (the famous 'Tonbridge Wells 1' arrival!). Added to the track miles are the speed requests for sequencing which result in flap extension (more fuel) and sometimes (737) gear down from as far out as 14 miles. In this situation, fuel is rapidly becoming the main focal point in the cockpit, and it is useful to be able to plan how much will be used from the hold in assessing the diversion decision.
Where does everyone stand on this?
Would the drivers prefer, like me, to stay in the hold for one more turn, and then get a slick, 10 mile final after, say, 30 track miles with few speed requests? Diversion from 7000' in the hold is a lot easier too!
How easy would it be for the controllers to adjust the procedures to allow this?
This one is for the LGW approach/director controllers and the 'drivers'. I tried floating this through my company a while ago but with no response, so its time to see what pprune can make of it!
When LGW starts to get busy and aircraft are holding, it is not uncommon to be taken off the hold and given extended vectoring, with speed control, round to the final approach. This can vary between 30 and 80 miles and the biggest variation I have seen in fuel used from the hold in a 737 is between 300 and 800 kgs (the famous 'Tonbridge Wells 1' arrival!). Added to the track miles are the speed requests for sequencing which result in flap extension (more fuel) and sometimes (737) gear down from as far out as 14 miles. In this situation, fuel is rapidly becoming the main focal point in the cockpit, and it is useful to be able to plan how much will be used from the hold in assessing the diversion decision.
Where does everyone stand on this?
Would the drivers prefer, like me, to stay in the hold for one more turn, and then get a slick, 10 mile final after, say, 30 track miles with few speed requests? Diversion from 7000' in the hold is a lot easier too!
How easy would it be for the controllers to adjust the procedures to allow this?
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You´ve said it all. I´m with you on that one BOAC. Much better to stay in the hold, clean, than to have 80 
"dirty" trackmiles around the countryside..
I´m sure that the ATCO`s can explain the reasons for doing this, but a great subject for some discussion.
"dirty" trackmiles around the countryside..I´m sure that the ATCO`s can explain the reasons for doing this, but a great subject for some discussion.
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Hi BOAC have been in the same situation in the last 2 days. Given an EAT overhead AMS (PAMPUS)inbound from ARN told to slow down and informed this will not effect our place in the queue, this sort of info is invaluble and I would say well done to London ATC.
Entered the hold at TIMBA keeping a track of fuel we were burning turns out 3 times in FULL round the hold with decents in every one we were burning 170kg each hold.
At the specified EAT we were taken out the hold and vectored downwind for 26L, most Captains I know will want between 300Kg and 500kg from the hold to start an approach, for planning we bargained on 400kg we actually used 780kg from the hold to landing and landed above reserves but vastly below planned remaining! In the event of a Go around we would be in PAN conditions, although the WX had inproved above CAT3 it was still wavering around on CAT2 limits.
Two things spring to mind and for all the ATCers out there this is not a critiscism, are airports judged by the time aircraft spend in the hold?, if so is it therefore beneficial to pull aircraft out the hold and vector them across west sussex and kent to keep this time to a minimum?
and.... when given a EAT how far can it slip??, since when planning to divert or commit the EAT is one of the variables in the equation.
Also what use is an EAT given the circumstances above do we need to plan for EAT plus 800kg to err on the safe side?
Last but not least I thought it was a great offer from the Continental 777 in the hold to swap places with a BA 737 who was on the verge of diverting! Thanks
Entered the hold at TIMBA keeping a track of fuel we were burning turns out 3 times in FULL round the hold with decents in every one we were burning 170kg each hold.
At the specified EAT we were taken out the hold and vectored downwind for 26L, most Captains I know will want between 300Kg and 500kg from the hold to start an approach, for planning we bargained on 400kg we actually used 780kg from the hold to landing and landed above reserves but vastly below planned remaining! In the event of a Go around we would be in PAN conditions, although the WX had inproved above CAT3 it was still wavering around on CAT2 limits.
Two things spring to mind and for all the ATCers out there this is not a critiscism, are airports judged by the time aircraft spend in the hold?, if so is it therefore beneficial to pull aircraft out the hold and vector them across west sussex and kent to keep this time to a minimum?
and.... when given a EAT how far can it slip??, since when planning to divert or commit the EAT is one of the variables in the equation.
Also what use is an EAT given the circumstances above do we need to plan for EAT plus 800kg to err on the safe side?
Last but not least I thought it was a great offer from the Continental 777 in the hold to swap places with a BA 737 who was on the verge of diverting! Thanks
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crp5
You say how little fuel you burnt in the hold. You then go on to say you used slightly greater than expected for vectoring.
You then go on to say that had you gone around you would of been close to declaring a state of urgency.
What I find a little puzzling is that you could be so tight on fuel with CAT 3 conditions although improving.
Out of interest how much extra did you take given the weather?
You say how little fuel you burnt in the hold. You then go on to say you used slightly greater than expected for vectoring.
You then go on to say that had you gone around you would of been close to declaring a state of urgency.
What I find a little puzzling is that you could be so tight on fuel with CAT 3 conditions although improving.
Out of interest how much extra did you take given the weather?
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500Kg extra enough for 10-15mins extra holding, but added to cont of 15mins that gave us 25-30 mins for holding, kept at FL310 as opposed to a planned FL350 over 2hrs 40 mins, therefore burnt some of the extra fuel loaded , therefore by the time we had left the hold on heading 270 gone west for 15 miles then turned onto a heading of 080 for downwind, some flown at 180kts finally intercepting LOC at 16 miles, by the time we got on the ground we had just started to eat into our DIV fuel,which as you know is well below planned remaining which takes into account you have not burnt CONT fuel,in the event of a GO AROUND what would YOU have done? I can only agree with BOAC that it must be better sitting in the hold clean than being vectored all over the south of england!
Since CAT3 conditions were a prob 30 at 04.00 GMT (FCO something or other states that only prob40 should be used for fuel planning)and that by the time we arrived the forcast was for 9999 nil wind, can you perhaps give me the benefit of your vast experience and explain the decisions YOU would have made?
(figures quoted above are approximate, amount of holding time available depends on ambient wx conditions and aircraft weight, amongst other things!)
[This message has been edited by CRP5 (edited 17 May 2001).]
Since CAT3 conditions were a prob 30 at 04.00 GMT (FCO something or other states that only prob40 should be used for fuel planning)and that by the time we arrived the forcast was for 9999 nil wind, can you perhaps give me the benefit of your vast experience and explain the decisions YOU would have made?
(figures quoted above are approximate, amount of holding time available depends on ambient wx conditions and aircraft weight, amongst other things!)
[This message has been edited by CRP5 (edited 17 May 2001).]
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BOAC - I don't mind extended vectors, provided that 2 seconds is taken to tell us that it will be just that. But, I do think director could help us by leaving each jet at say FL70 until the 21 mile point (stay out of the bumps for the peeps, keep a lower noise profile), or (as I have heard only a few times) - Descend your discretion 4000' etc. Agree with your point about early speed reduction. Having gear down from 14 miles at 160kt/3000' eats fuel.
CCC...ough
CCC...ough
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Flanker thank you for your comments, I really do not want this to become a debate about how much fuel you need to take etc, BOAC has made a valid point about extended radar vectoring when it would be better certainly from my point of view to stay and decend in the hold then make an approach.
I used the example in my first post to try and help reinforce that point.I think that there is more than likley ,from an ATC point of view a reason why they do this, but at the moment I can,t see the bigger picture.
I used the example in my first post to try and help reinforce that point.I think that there is more than likley ,from an ATC point of view a reason why they do this, but at the moment I can,t see the bigger picture.
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As a gatwick director, I do tend to bring the aircraft off early and have a long circuit. But this should always be flown at min stack and clean speed, I don't believe in early speed reduction or early descent.
If we are providing six mile spacing to an eight mile final, then tower asks us to 'pack' there are simply not enough aircraft in the sequence. i would say a 12-14 mile final is the optimum.(this also allows us to use speed control to refine the spacing). In my experience, a consistent 8 mile final is not the most efficient for runway utilisation.
In the summer mornings, there is a genuine shortage of levels in the two stacks. Gatwick approach controllers have a large amount of airspace, so by using that to have a few extra aircraft in the sequence, we remove some of the pressure for levels our terminal control colleagues suffer from.
we are not judged on delays ( in fact there is constant pressure from the airlines to reduce flow no matter the airborne delays),however it does seem more beneficial to let you fly straight and level for 15 miles west, then 15 miles east, than to let you fly twice round a racetrack pattern. Isn't it more comfortable ?
Finally, at heathrow, you can expect 180 kts from 25-30 miles out (through biggin in any southerly wind), 15+ mile final and 160 kts from as far out as 15 miles. Do you carry more extra fuel for heathrow than gatwick ?
If we are providing six mile spacing to an eight mile final, then tower asks us to 'pack' there are simply not enough aircraft in the sequence. i would say a 12-14 mile final is the optimum.(this also allows us to use speed control to refine the spacing). In my experience, a consistent 8 mile final is not the most efficient for runway utilisation.
In the summer mornings, there is a genuine shortage of levels in the two stacks. Gatwick approach controllers have a large amount of airspace, so by using that to have a few extra aircraft in the sequence, we remove some of the pressure for levels our terminal control colleagues suffer from.
we are not judged on delays ( in fact there is constant pressure from the airlines to reduce flow no matter the airborne delays),however it does seem more beneficial to let you fly straight and level for 15 miles west, then 15 miles east, than to let you fly twice round a racetrack pattern. Isn't it more comfortable ?
Finally, at heathrow, you can expect 180 kts from 25-30 miles out (through biggin in any southerly wind), 15+ mile final and 160 kts from as far out as 15 miles. Do you carry more extra fuel for heathrow than gatwick ?
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CRP5
I will ignore your sarcasm in response to my genuine enquiry.
I wasn't there and so I must assume you made a prudent decision regarding fuel.
In general terms if I see PROBs on the forecast especially relating to fog that indicates to me that the forecaster isn't sure and if he isn't then I am certainly not. I generally load an extra 30 mins on top of the FP figure for those circumstances.
I agree with BOAC's original post that extended vectors and speed control below clean speed are a problem (more so on the 737).
My experience of the US (considerable) is that the controllers will vector an aircraft many miles rather than put it into a holding pattern. Makes fuel required for the approach something of a guess.
I will ignore your sarcasm in response to my genuine enquiry.
I wasn't there and so I must assume you made a prudent decision regarding fuel.
In general terms if I see PROBs on the forecast especially relating to fog that indicates to me that the forecaster isn't sure and if he isn't then I am certainly not. I generally load an extra 30 mins on top of the FP figure for those circumstances.
I agree with BOAC's original post that extended vectors and speed control below clean speed are a problem (more so on the 737).
My experience of the US (considerable) is that the controllers will vector an aircraft many miles rather than put it into a holding pattern. Makes fuel required for the approach something of a guess.
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I only work Heathrow traffic but find it difficult to believe an 80-mile circuit! With the available airspace I would not have thought that possible.
We try to maintain 210kts until base leg, then 180.... but there are a number of crews who ask to slow down to 180 long before a base leg..
Occasionally is the inner stacks are getting full we might bring traffic off early and give it an extended circuit to give us another level in the stack, but we'd keep you at 210kts+ for the countryside tour.
Haven't the last few days been such fun in the London TMA??!!
We try to maintain 210kts until base leg, then 180.... but there are a number of crews who ask to slow down to 180 long before a base leg..
Occasionally is the inner stacks are getting full we might bring traffic off early and give it an extended circuit to give us another level in the stack, but we'd keep you at 210kts+ for the countryside tour.
Haven't the last few days been such fun in the London TMA??!!
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Heathrow, the 80 miles is most certainly possible, but remember I am talking track miles from the hold. Take me 15 miles west off TIMBA, then back 15 past TIMBA again, and out for a 15 mile final, plus base leg and turns and .........80........easy!
Just to clear any doubts-there is NO criticism of the excellent LONDON ATC implied here, just a go at getting things better for us drivers from a position of ignorance of your problems.
[This message has been edited by BOAC (edited 17 May 2001).]
Just to clear any doubts-there is NO criticism of the excellent LONDON ATC implied here, just a go at getting things better for us drivers from a position of ignorance of your problems.
[This message has been edited by BOAC (edited 17 May 2001).]
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So how do you like to be handled ?
Us ATCO's don't get much feedback on how to refine the service.
What type do you fly/airline,what length final is ideal and what is the best point to reduce speed ?
do you get enough information-no. in sequence, distance to run, etc ?
We can only provide the very best service if you tell us what you want.
Us ATCO's don't get much feedback on how to refine the service.
What type do you fly/airline,what length final is ideal and what is the best point to reduce speed ?
do you get enough information-no. in sequence, distance to run, etc ?
We can only provide the very best service if you tell us what you want.
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This is my first "season", so I haven't seen the busiest it can get yet, but so far, into LGW it's been short dog legs before feed-in, and always a continuous descent. The judgement call for me has been in getting rid of energy (757), and when to plan the descent point - an early call from ATC about likely routeing obviously helps, but the ATC service has been really slick so we've not had to burn any extra fuel. I imagine the dogleg technique makes it easier for a controller to see in plan form when to come off the dog leg for sequencing, rather than off a stack. It is great if you're always in a descent, but obviously if the legs too long then you'd have to level off and use fuel. If the leg's too long (how can legs be too long?!!!) then it would have been better to be up in the stack with lower fuel burn. I guess that's where the controllers judgement comes in. Am I right?
There's stuff I don't know about here, but I'd like to visit the ATC to see it from their point of view, and learn their side of it.
What I've learnt from this thread is to make sure there's plenty of the go juice when recovering at LGW at the busy times. So far I've had good guidance from my capts on when it gets busy at LGW (one of them used to be a controller but wanted an easier life!)
Anyhow, I'm impressed at how they do their job.
There's stuff I don't know about here, but I'd like to visit the ATC to see it from their point of view, and learn their side of it.
What I've learnt from this thread is to make sure there's plenty of the go juice when recovering at LGW at the busy times. So far I've had good guidance from my capts on when it gets busy at LGW (one of them used to be a controller but wanted an easier life!)
Anyhow, I'm impressed at how they do their job.
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In a perfect world, as I said at the start, it is better from the fuel point of view to do one more hold pattern and get a min distance to a 10 mile final at min clean all the way to the GP.
We all know that sometimes airspace/traffic does not permit this. My a/c is 737, but there is not much point in talking 'standard' clean speeds (or is there?).
How close could you get to the ideal (assuming other pilots want the same)?
We all know that sometimes airspace/traffic does not permit this. My a/c is 737, but there is not much point in talking 'standard' clean speeds (or is there?).
How close could you get to the ideal (assuming other pilots want the same)?
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I think the Pilots have a justified argument here. We are generally made aware of fuel burn characteristics,but I am always willing to listen to any aircrafts Min clean speed and vector accordingley ( I dont work at KK or LL,where the pressures are higher).
Howevever what must be realised is that if we dont get them off the bottom, then they are going to build up rapidly at the top.
That may be great for fuel burn, holding at 350!, but its cr*p for airspace utilisation.
You can have 4 downwind at or descending to the same altitude ,but only one in the hold at a particular altitude/FL.
It was said earlier that this topic is not about fuel carry. I disagree the rules we were taught as ATC'ers seem to be so different from what the present situation is.
I recentley had a handling agent call me about one of their aircraft,still 40 miles short of the holding facility,asking what the likely delay was because the aircraft had 15 minutes fuel left ( we were holding at the time, not normal,but due to adverse ,unforseen weather). When reminded that we were on a recorded telephone line the agent hung up swiftly.
Another get out these days, seems to be, at airports with more than one runway,using the second runway as your diversion field for fuel planning . Even if the second runway could be made unusable by a problem on the first.
Accountants and Grocers...Napoleon had it right!
Howevever what must be realised is that if we dont get them off the bottom, then they are going to build up rapidly at the top.
That may be great for fuel burn, holding at 350!, but its cr*p for airspace utilisation.
You can have 4 downwind at or descending to the same altitude ,but only one in the hold at a particular altitude/FL.
It was said earlier that this topic is not about fuel carry. I disagree the rules we were taught as ATC'ers seem to be so different from what the present situation is.
I recentley had a handling agent call me about one of their aircraft,still 40 miles short of the holding facility,asking what the likely delay was because the aircraft had 15 minutes fuel left ( we were holding at the time, not normal,but due to adverse ,unforseen weather). When reminded that we were on a recorded telephone line the agent hung up swiftly.
Another get out these days, seems to be, at airports with more than one runway,using the second runway as your diversion field for fuel planning . Even if the second runway could be made unusable by a problem on the first.
Accountants and Grocers...Napoleon had it right!